1. Field of the Invention
The present invention relates to a hot water supply system that cooperatively operates a plurality of water heaters.
2. Description of the Related Art
Conventionally, a hot water supply system has been known in which control units of water heaters are connected to one combining unit and this unit increases and decreases the number of water heaters in operation according to water supply flow rates detected by flow rate sensors included in the respective water heaters in operation (e.g. Japanese Patent Laid-Open No. 2002-357361).
Further, a hot water supply system has been known in which two water heaters are connected to each other without use of a combining unit in a communicable manner, one of the water heaters set to master and the other is set to slave, and, in a case where the master water heater is independently operated, if it is detected that hot water supply capacity is insufficient, the slave water heater is further operated (see e.g. Japanese Patent Laid-Open No. 2003-222399).
According to the hot water supply system described in Japanese Patent Laid-Open No. 2003-222399, in case of failure of one of the master and the slave, the system continues operation of the other water heater that is not in failure.
The hot water supply system described in Japanese Patent Laid-Open No. 2003-222399 switches the master and the slave with each other by means of presence or absence of a short circuit of connector terminals (14e and 14f or 15e and 15f) of the respective water heaters. In case of failure of any one of the water heaters, the system independently operates the water heater that is not in failure.
In a case where water heaters are cooperatively operated while one of the water heaters functions as a master and the other functions as a slave, if the number of the water heaters is two, in case of failure of the master water heater, it suffice to independently operate the one water heater that is not in failure. The relationship between the master and the slave is insignificant.
However, in a case where at least three water heaters are cooperatively operated while one of the water heaters functions as a master and the others function as slaves, in case of failure of the master water heater, an operation is required to repair the master water heater in failure or to cause a short circuit at a connector terminal of any of the slave water heaters and switch the heater to master. Accordingly, either case has an inconvenience that cooperative operation is incapable until such measures are taken.
In a case of adopting specifications that includes a remote control for remotely operating a hot water supply system and sets operation conditions, such as a hot water supply temperature, by means of communication between the master water heater and the remote control, if the master water heater fails and communication between the master water heater and the remote control becomes incapable, an inconvenience that the hot water supply system cannot remotely be operated by means of the remote control occurs.
The present invention is made in view of the background. It is an object of the present invention to provide a hot water supply system that can solve various inconveniences caused by failure of a master water heater in a case of cooperatively operating a plurality of water heaters while one of the water heaters functions as the master and the other functions as a slave.